肝表面の微細構造

特に腹水発生機序に関して

抄録

Under the electron microscope, the liver surface of normal rats has two layers, the outer mesothelial cell layer of the peritoneum and the inner connective tissue layer which consists of fibroblasts and fiber bundles. The besement membrane, about 400 to 500 A in width, is osserved beneath the mesothelial layer. The mesothelial cell of the peritoneum has numerous microvilli, 1 to 2μ in length, on the cell surface facing the peritoneal cavity and occasionally appear to be polypous at the top. The pinocytic invaginations are frequently observed on the cell membrane facing both the peritoneal cavity and the basement membrane. The space between the connective tissue layer and the liver cell sometimes appears to be directly communicating with the sinusoid through an intercellular space of the liver cell.
Radioactive gold collids were infused into the portal vein of the rat in which the hepatic vein had been narrowed, and the fluid oozing from the liver surface was absorbed with pieces of gauze which were changed every 15 minutes. Considerable radioactivity was demonstrated particularly in the first 15 minutes. Electron micrographs also revealed gold particles pinocytosed into the cytoplasm of the mesothelial cell.
The liver surface of rats with carbon tetrachloride induced cirrhosis and ascites had a thick mesothelial cell layer and a remarkably widened connective tissue layer, containing macrophages, plasma cells and dilated lymph vessels. The mesothelial cell of the liver surface in cirrhosis with ascites had many vesicles in the cytoplasm and pinocytic invagination appeared to be increased in number along the cell membranes, and the intercellular space beneath the tight junction between two mesothelial cells was frequently dilated, but no rupture of the junction was noted. Radioactive gold colloids, infused into the portal vein of cirrhotic rats with ascites, were clearly detected on the liver surface between 15 to 30 minutes after the infusion. Electron micrographs also revealed gold particles in the mesothelial cell of the liver surface.
These findings suggest that the liver surface is the most important source of ascites, in its formation and that the mesothelial cell is capable of transporting fluid and some colloids.